Respuesta :

Step-by-step explanation:

The sequence is geometric as the ratio between consecutive terms is common:

  • 3/-15 = - 1/5
  • -15/75 = - 1/5

The first term is:

  • t₁ = 75
  • r = - 1/5

The explicit formula is:

  • tₙ = t₁rⁿ⁻¹

Substitute values of the first term and common ratio to get:

  • tₙ = 75*(- 1/5)ⁿ⁻¹